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Rivet analyses reference

OPAL_1997_I440721

Event Shapes at 161 GeV
Experiment: OPAL (LEP)
Inspire ID: 440721
Status: VALIDATED
Authors:
  • Peter Richardson
References:
  • Z.Phys. C75 (1997) 193-207
Beams: e- e+
Beam energies: (80.5, 80.5) GeV
Run details:
  • e+e- to hadrons

Event shapes at 161 GeV. Only the evnet shapes are implemented, not the mean values, or the cone jet observables.

Source code: OPAL_1997_I440721.cc
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// -*- C++ -*-
#include "Rivet/Analysis.hh"
#include "Rivet/Projections/Beam.hh"
#include "Rivet/Projections/FinalState.hh"
#include "Rivet/Projections/ChargedFinalState.hh"
#include "Rivet/Projections/Sphericity.hh"
#include "Rivet/Projections/Thrust.hh"
#include "Rivet/Projections/FastJets.hh"
#include "Rivet/Projections/ParisiTensor.hh"
#include "Rivet/Projections/Hemispheres.hh"

namespace Rivet {


  /// @brief event shapes at 161
  class OPAL_1997_I440721 : public Analysis {
  public:

    /// Constructor
    DEFAULT_RIVET_ANALYSIS_CTOR(OPAL_1997_I440721);


    /// @name Analysis methods
    //@{

    /// Book histograms and initialise projections before the run
    void init() {

      // Initialise and register projections
      // Projections
      declare(Beam(), "Beams");
      const FinalState fs;
      declare(fs, "FS");
      const ChargedFinalState cfs;
      declare(cfs, "CFS");
      declare(FastJets(fs, FastJets::DURHAM, 0.7), "DurhamJets");
      declare(Sphericity(fs), "Sphericity");
      declare(ParisiTensor(fs), "Parisi");
      const Thrust thrust(fs);
      declare(thrust, "Thrust");
      declare(Hemispheres(thrust), "Hemispheres");

      // Book histograms
      book(_h_thrust    ,  3,1,1);
      book(_h_major     ,  4,1,1);
      book(_h_minor     ,  5,1,1);
      book(_h_aplanarity,  8,1,1);
      book(_h_oblateness,  6,1,1);
      book(_h_C         ,  9,1,1);
      book(_h_rhoH      , 10,1,1);
      book(_h_sphericity,  7,1,1);
      book(_h_totalB    , 11,1,1);
      book(_h_wideB     , 12,1,1);
      book(_h_y23       , 20,1,1);
      book(_h_mult      , 26,1,1);
      book(_h_pTin      , 21,1,1);
      book(_h_pTout     , 22,1,1);
      book(_h_y         , 23,1,1);
      book(_h_x         , 24,1,1);
      book(_h_xi        , 25,1,1);
      book(_sumW,"/TMP/sumW");
    }


    /// Perform the per-event analysis
    void analyze(const Event& event) {
      // Even if we only generate hadronic events, we still need a cut on numCharged >= 2.
      const FinalState& cfs = apply<FinalState>(event, "CFS");
      if (cfs.size() < 2) vetoEvent;
      _sumW->fill();
      
      // Get beams and average beam momentum
      const ParticlePair& beams = apply<Beam>(event, "Beams").beams();
      const double meanBeamMom = ( beams.first.p3().mod() +
                                   beams.second.p3().mod() ) / 2.0;
      
      // Thrust related
      const Thrust& thrust = apply<Thrust>(event, "Thrust");
      _h_thrust    ->fill(thrust.thrust()     );
      _h_major     ->fill(thrust.thrustMajor());
      _h_minor     ->fill(thrust.thrustMinor());
      _h_oblateness->fill(thrust.oblateness());

      // Sphericity related
      const Sphericity& sphericity = apply<Sphericity>(event, "Sphericity");
      _h_sphericity->fill(sphericity.sphericity());
      _h_aplanarity->fill(sphericity.aplanarity());
      
      // C parameter
      const ParisiTensor& parisi = apply<ParisiTensor>(event, "Parisi");
      _h_C->fill(parisi.C());

      // Hemispheres
      const Hemispheres& hemi = apply<Hemispheres>(event, "Hemispheres");

      _h_rhoH  ->fill(hemi.scaledMhigh());
      _h_wideB ->fill(hemi.Bmax());
      _h_totalB->fill(hemi.Bsum());
      
      // Jets
      const FastJets& durjet = apply<FastJets>(event, "DurhamJets");
      const double y23 = durjet.clusterSeq()->exclusive_ymerge_max(2);
      _h_y23->fill(y23);

      // charged particles
      _h_mult->fill(cfs.particles().size());
      for (const Particle& p : cfs.particles()) {
        const Vector3 mom3  = p.p3();
        const double energy = p.E();
        const double pTinT  = dot(mom3, thrust.thrustMajorAxis());
        const double pToutT = dot(mom3, thrust.thrustMinorAxis());
      	_h_pTin ->fill(fabs(pTinT/GeV) );
      	_h_pTout->fill(fabs(pToutT/GeV));
        const double momT = dot(thrust.thrustAxis(), mom3);
        const double rapidityT = 0.5 * std::log((energy + momT) / (energy - momT));
      	_h_y->fill(fabs(rapidityT));
        const double mom = mom3.mod();
        const double scaledMom = mom/meanBeamMom;
        const double logInvScaledMom = -std::log(scaledMom);
        _h_xi->fill(logInvScaledMom);
        _h_x ->fill(scaledMom      );
      }
    }


    /// Normalise histograms etc., after the run
    void finalize() {
      scale(_h_thrust    ,1./ *_sumW);
      scale(_h_major     ,1./ *_sumW);
      scale(_h_minor     ,1./ *_sumW);
      scale(_h_aplanarity,1./ *_sumW);
      scale(_h_oblateness,1./ *_sumW);
      scale(_h_C         ,1./ *_sumW);
      scale(_h_rhoH      ,1./ *_sumW);
      scale(_h_sphericity,1./ *_sumW);
      scale(_h_totalB    ,1./ *_sumW);
      scale(_h_wideB     ,1./ *_sumW);
      scale(_h_y23       ,1./ *_sumW);
      scale(_h_mult      ,200./ *_sumW);
      scale(_h_pTin      ,1./ *_sumW);
      scale(_h_pTout     ,1./ *_sumW);
      scale(_h_y         ,1./ *_sumW);
      scale(_h_x         ,1./ *_sumW);
      scale(_h_xi        ,1./ *_sumW);
      // mean multiplicity
      double nch     = _h_mult->xMean();
      double nch_err = _h_mult->xStdErr();
      Scatter2DPtr m_ch;
      book(m_ch,2,1,1);
      m_ch->addPoint(sqrtS(),nch,0.5,nch_err);
    }

    //@}


    /// @name Histograms
    //@{
    Histo1DPtr _h_thrust,_h_major,_h_minor,_h_aplanarity,_h_oblateness,_h_C,_h_rhoH,_h_sphericity;
    Histo1DPtr _h_totalB,_h_wideB,_h_y23,_h_mult,_h_pTin,_h_pTout,_h_y,_h_x,_h_xi;
    CounterPtr _sumW;
    //@}


  };


  // The hook for the plugin system
  DECLARE_RIVET_PLUGIN(OPAL_1997_I440721);


}